In the season five finale, Jenny is in the diner with Gibbs old partner. She finds a box of tea bags and laments they don't have water and that he doesn't seem "to be the tea drinking type," and he says he isn't. Later he is seen with Gibbs at another diner, and he is dipping a tea bag in a cup of hot water.
Mike (Gibbs former partner) actually states that he only likes one type of tea at the beginning of the "tea" discussion with Jen. He is probably drinking that type of tea when you see him later with Gibbs.
At the start of the "tea" discussion, Mike Franks states that he only likes one type of tea. Perhaps he is drinking that type of tea when you see him later with Gibbs.